Thesis
The effects of mechanical pruning on yield, fruit quality and vegetative growth in apple and sweet cherry
Washington State University
Master of Science (MS), Washington State University
05/2016
Handle:
https://hdl.handle.net/2376/100186
Abstract
Pruning is a labor- and time-demanding operation that generally represents the second greatest annual expense for tree fruit growers worldwide. As orchardists adopt new planar orchard systems there is improved potential for the mechanization of orchard operations, including pruning. This research project compared standard hand pruning practices with mechanical pruning in sweet cherry (Prunus avium L.) and apple (Malus domestica Borkh.) commercial orchards to better understand the effects of mechanization on yield, fruit quality and vegetative growth. In ‘Tieton’/‘Gisela5’ sweet cherry, treatments compared postharvest hand pruning with mechanical pruning and the combination of both approaches over two years. Mechanical pruning required three passes per tree yet was 23 and 29 times faster than hand pruning in 2014 and 2015, respectively (i.e., 16 and 15 s/tree). In 2015, the combination of mechanical, followed by hand pruning was 66% more efficient (kg wood/min/tree) than hand pruning alone. There was no effect of pruning treatment on yield. Current season shoot regrowth from trees pruned mechanically was significantly higher (ca. +32%) than new extension growth from hand pruned trees. A separate trial compared timing of tree topping, mimicking the operation of mechanical pruning. Hand topping performed 2 and 3 months after full bloom removed approximately 520% (i.e., 6 times) more wood than earlier pruning; however, the greatest new extension growth was observed from trees pruned in the winter (ca. +95%). In ‘Fuji’/’Nic29’ apple, trees were hedged mechanically or by hand at different timings (winter, summer 12-15 leaves, and summer 20 leaves). Winter mechanical pruning was 2.3 times faster than hand pruning in 2014 (i.e., 8 s/tree). Trees pruned mechanically exhibited ca. 53% higher return bloom compared to those pruned by hand. Yield from trees pruned by hand in the winter and mechanically in the summer was ca. 32% and 41% lower than those pruned only in the winter manually or with the machine, respectively. A preliminary economic assessment indicates that mechanical pruning can reduce production costs and improve labor efficiency. These results show promise for mechanizing pruning in apple and sweet cherry orchards trained to vertical fruiting wall architectures.
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Details
- Title
- The effects of mechanical pruning on yield, fruit quality and vegetative growth in apple and sweet cherry
- Creators
- Jacqueline Alexandra Gordon Nunez
- Contributors
- Matthew David Whiting (Chair)Stefano Musacchi (Committee Member) - Washington State University, Horticulture, Department ofKaren Marie Lewis (Committee Member) - Washington State University, WSU Extension ANR
- Awarding Institution
- Washington State University
- Academic Unit
- Horticulture, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Number of pages
- 214
- Identifiers
- 99900524808601842
- Language
- English
- Resource Type
- Thesis